Porous carbon derived from waste polystyrene foam for supercapacitor

Polystyrene, one of the classical plastic, has caused serious environmental problems due to overuse and inability to recycle effectively. Transforming it into functional carbon materials is one of the effective ways to recycle polystyrene and other waste plastics, which has drawn the attention. In this study, we have developed a facile and efficient method for the preparation of three-dimensional (3D) network structure porous carbon (PC) via the Friedel–Crafts reaction with waste polystyrene serves as carbon source. Notably, the constructed carbonyl (–CO–) cross-linking bridges between the linear polystyrenes provide the resulting hierarchical porous polystyrene with a high cross-linking density and amounts of oxygen atoms to achieve the carbonizability of cross-linking polystyrene framework. Moreover, silica particles created more porous structure for carbon material. The prepared PC showed large specific surface area and 3D porous structure and exhibited good capacitance and electrochemical stability as electrode materials for supercapacitor.     

Synthesis and characterization of activated carbon/conducting polymer composite electrode for supercapacitor applications

Activated carbon is prepared from coconut shell by heating it around 500?°C for 2 h in a muffle furnace. This method is one of the easiest and most economical methods for the synthesis of Activated carbon. The dried coconut shell is carbonized and it is treated with KOH in the ratio of 1:3 carbon-activating agent (KOH) and the resulting slurry is dried in an oven at 60?°C for overnight. The dried mass is further activated at 450?°C then it is washed with an acid solution to remove KOH. The surface area of the synthesized activated carbon can be obtained by using nitrogen absorption–desorption experiment. Conducting polymer such as polyaniline prepared by oxidative polymerization of the respective monomer in tetrafluoroboric acid solution using potassium persulphate as an oxidant. The structure and doping of polyaniline were studied by FTIR, UV and Cyclic voltammetry studies. The conducting polymer is mixed with AC and prepared composites were characterized by UV, FTIR, and CV. The specific capacitance of composites calculated from charge–discharge at 0.5 mA g^??1 was found to be 99.6 Fg^??1 and for cyclic voltammetry, at the scan rate of 2 mV s^??1, it is 77 Fg^??1.     

Fabrication of carbon capsules with hierarchical pore structures

Carbon capsules with hierarchical pore structures were fabricated by using core-shell silica nanoparticles as templates and phenolic resin as a carbon precursor. Carbon capsules with hierarchical pore structures were obtained via in-situ polymerization of the phenolic resin on the surface of the silica nanoparticles followed by the carbonization and removal of the silica templates. The hierarchically pored carbon capsules exhibited multimodal porosity with a high specific surface area (approximately 1834 m2/g) and a large pore volume (approximately 1.83 cm3/g).     

Nanoarchitectonics of nitrogen-doped porous carbon derived from leather wastes for solid-state supercapacitor

Journal of Materials Science: Materials in Electronics - Leather solid wastes not only endanger the environment, but also lead to a significant waste of biomass resources. The efficient utilization...     

Bioresorbable and bioactive polymer/Bioglass® composites with tailored pore structure for tissue engineering applications

An overview about the development of porous bioresorbable composite materials for applications as scaffolds in tissue engineering is presented. A thermally induced phase separation method was developed to fabricate porous foam-like structures of poly(lactide-co-glycolide) (PLGA) containing bioactive glass particle additions (up to 50 wt.%) and exhibiting well-defined, oriented and interconnected porosity. The in vitro bioactivity and the degradability of the composite foams were investigated in contact with phosphate buffer saline (PBS). Weight loss, water absorption and molecular weight measurements were used to monitor the polymer degradation after incubation periods of up to 7 weeks in PBS. It was found that the presence of bioactive glass retards the polymer degradation rate for the time period investigated. The present results show a way of controlling the in vitro degradation behaviour of PLGA porous composite scaffolds by tailoring the concentration of bioactive glass.     

Activated carbon–carbon nanotube composite porous film for supercapacitor applications

Activated carbon/carbon nanotube composite electrodes have been assembled and tested in organic electrolyte (NEt₄BF₄ 1.5 M in acetonitrile). The performances of such cells have been compared with pure activated carbon-based electrodes. CNTs content of 15 wt.% seems to be a good compromise between power and energy, with a cell series resistance of 0.6 Ω cm² and an active material capacitance as high as 88 F g⁻¹.     

Nitrogen plasma functionalization of carbon nanotubes for supercapacitor applications

Surface modification of carbon nanotubes with a simple and fast plasma treatment allows for the design of new nanomaterials with enhanced electrochemical properties. Both structural disorder and nitrogen concentration of the nanotubes increase after a nitrogen plasma treatment. The effect of plasma power and nitrogen pressure on the charge storage capability of the nanotubes has been investigated in detail. Depending on the plasma conditions, nitrogen functionalities such as quaternary nitrogen in the basal planes, and pyrrolic groups at the edges are introduced in the nanotubes structure. The potential difference between anodic and cathodic peaks of the Fe³⁺/Fe²⁺ redox couple decreases from 102 mV down to 75.7 mV after the nitrogen plasma treatment, which accounts for an increased reversibility of the electron transfer process between nanotubes and electrolyte. Moreover, the treated nanotubes show a significant increase in their specific capacitance from 22 up to 55 F g^?1 at a scan rate of 10 mV s^?1 in a 0.1 M Na₂SO₄ solution. Pyridinic and pyrrolic functionalities are found to play an important role in enhancing the reversibility and specific capacitance of the obtained electrodes.     

3D photonic crystals with a hierarchical pore structure

Perfect 3D film photonic crystals are synthesized from submicron spherical silica particles consisting of a nonporous core and a mesoporous shell. The obtained photonic crystals with a hierarchical pore arrangement—transport macropores between particles and mesopores inside the shell—are promising for application in optical gas sensors.     

Freestanding hierarchical porous carbon film derived from hybrid nanocellulose for high-power supercapacitors

Nanocellulose is a sustainable and eco-friendly nanomaterial derived from renewable biomass.In this study,we utilized the structural advantages of two types of nanocellulose and fabricated freestanding carbonized hybrid nanocellulose films as electrode materials for supercapacitors.The long cellulose nanofibrils (CNFs) formed a macroporous framework,and the short cellulose nanocrystals were assembled around the CNF framework and generated micro/mesopores.This two-level hierarchical porous structure was successfully preserved during carbonization because of a thin atomic layer deposited (ALD) Al2O3 conformal coating,which effectively prevented the aggregation of nanocellulose.These carbonized,partially graphitized nanocellulose fibers were interconnected,forming an integrated and highly conductive network with a large specific surface area of 1,244 m2·g-1.The two-level hierarchical porous structure facilitated fast ion transport in the film.When tested as an electrode material with a high mass loading of 4 mg·cm-2 for supercapacitors,the hierarchical porous carbon film derived from hybrid nanocellulose exhibited a specific capacitance of 170 F.g-1and extraordinary performance at high current densities.Even at a very high current of 50 A·g-1,it retained 65％ of its original specific capacitance,which makes it a promising electrode material for high-power applications.     

Spin-coating derived LSM-SDC films with uniform pore structure

LSM and SDC powders were synthesized by glycine-nitrates technique and LSM-SDC composite porous films are deposited by means of spin-coating process using ethyl cellulose as pore-forming material. According to the surface morphology and microstructure of cathode films identified with scanning electron microscopy (SEM), as the content of ethyl cellulose in slurry was increased, the pore distribution in films becomes more uniform and the pore size is getting smaller. It was found that while the slurry contains 10 wt.% ethyl cellulose and 90 wt.% LSM-SDC composite powders, the cathode film has a fine structure, which has smooth surface without cracks, uniform pore distribution, suitable pore size and three-dimensioned interconnected structure.     

Inelastic behavior of ceramics with hierarchical pore structure under compression

The compaction behavior is studied in Al₂O₃ ceramics with a pore space volume in the range from 35 to 60% and with the following three types of hierarchical pore structure: coarse porosity with a size of 80 to 100 μm, fine porosity with a size of 14 to 15 μm, and intermediate interblock porosity comprised of elongated (110–120 μm) porous microchannels formed as a result of zonal isolation during sintering. It is shown that the obtained hierarchical porous structure causes the formation of a hierarchical deformation structure in the volume of ceramics and leads to a decrease in the extent of destruction processes from the macroscopic scale in the case of unimodal ceramics to the microscale destruction comparable with the sizes of the blocks formed during sintering.     

Manganese-based coordination framework derived manganese sulfide nanoparticles integrated with carbon sheets for application in supercapacitor

Manganese sulfide (MnS) with high specific capacitance and low-cost merits, has been investigated as a potential electroactive material for supercapacitor. However, in practical application, MnS has been suffering from some disadvantageous issues such as insufficient electrical conductivity, serious particle agglomeration as well as huge volume change during continuous charges and discharges, which resulted in a limited specific capacitance, shortened working life and inferior rate performance. Engineering electrode materials with controlled nanostructure and composition is pivotal to improve electrichemical performance of supercapacitors. This paper introduces a facile in situ sulfuration method to fabricate MnS/NSC composite with Mn-hexamethylene tetramine coordination framework as precursor. The results indicated that MnS nanoparticles were highly dispersed and incorporated into nitrogen, sulfur-doped carbon microsheets in MnS/NSC composite. Carbon matrix effectively dispersed and confined the MnS nanoparticles, thus inhibiting aggregation, relieving volume change and retaining structural integrity. Moreover, the 2D conductive carbon matrix reduced the diffusion distance for ions and ensured fast electron delivery. As a result, MnS/NSC electrode delivered a tremendously boosted electrochemical performance for supercapacitor. A large capacitance value about 1881.8F/g was achieved at 1A/g. Even cycling for 3000 loops at 40 A/g, MnS/NSC electrode retained a large capacitance of 404.3F/g. Furthermore, an asymmetric capacitor based on assembly of MnS/NSC composite cathode and activated carbon anode was fabricated. As tested under a current density of 0.1 A/g, it delivered a capacitance of ～ 110.1F/g and achieved an energy density of 12.4 Wh kg^?1 along with a power density of 3.03 kW kg^?1. These results demonstrate the potential utilization of MnS/NSC composite as electrodes for energy conversion and storage devices and open up a route for material design for future energy storage devices.     

Nitrogen-doped hierarchical porous carbon materials derived from diethylenetriaminepentaacetic acid (DTPA) for supercapacitors

Nitrogen-doped porous carbon materials (NPCs) have been successfully fabricated by a simple one-step pyrolysis of diethylenetriaminepentaacetic acid (DTPA) in the presence of KOH. The as-synthesized NPCs displayed a high specific surface area (3214?m²?g^?1) and a well-defined porous structure when the annealing temperature reached 800?°C, which showed superior electrochemical performance as supercapacitor electrode materials. Electrochemical tests showed that the NPCs achieved an impressive specific capacitance of 323?F?g^?1 at a current density of 0.5?A?g^?1 in 6?M KOH aqueous solution and an outstanding cycle stability, negligible specific capacitance decay after 5000 cycles at 10?A?g^?1. This strategy offered a new insight into the preparation of novel carbon materials for the advanced energy storage devices, such as supercapacitors, fuel cells and lithium ion batteries.     

N-doped ordered mesoporous carbon spheres derived by confined pyrolysis for high supercapacitor performance

Herein, we report a confined pyrolysis strategy to prepare mesoporous carbon nanospheres by which surface area of carbon spheres is increased, pore size is enlarged and effective N-doping is achieved. In this method, the mesoporous polymer sphere as carbon precursor and 2-methylimidazole as nitrogen precursor are encapsulated in a compact silica shell which provides a confined nano-space for the pyrolysis treatment. The in situ generated gases from mesoporous polymer sphere and 2-methylimidazole under pyrolysis diffuse into the pores of mesoporous polymer sphere in the confined compact silica shell, resulting in increased surface area, larger pore size and N-doping due to self-activation effect. As electrodes in supercapacitor, the N-doped mesoporous carbon nanospheres exhibit a significantly enhanced specific capacitance of 326 F g⁻¹ at 0.5 A g⁻¹, which is 2 times higher than that of mesoporous carbon spheres under unconfined pyrolysis condition, exhibiting its potential for electrode materials with high performance.     

CO2捕集用具有多级孔结构纳米孔炭的制备（英文）

以模板法结合化学活化法制备了具有分级结构的纳米孔炭。分别利用氮气吸附法和热重分析法考查KOH活化程度对模板法制备中孔炭的孔结构的影响和不同孔结构的多孔炭对CO2的吸附性能。结果表明,KOH活化不仅增加了大量的微孔,而且使得模板脱除得到的中孔数量降低。中孔吸附CO2对孔表面的利用率最高,而中孔和微孔的合适配比更有利用综合提高CO2的吸附量。制备的纳米孔炭具有较高的CO2吸附量和较好的循环性能和稳定性。     

A self-healing carbon fibre reinforced polymer for aerospace applications

Self-healing is receiving increasing interest worldwide as a technology to autonomously address the effects of damage in composite materials. This paper describes the results of four point bend flexural testing (ASTM-D6272-02) of T300/914 carbon fibre reinforced epoxy with resin filled embedded hollow glass fibres (HGF) which provided a self-healing functionality. The study investigated the effect of the embedded HGF on the host CFRP mechanical properties and also the healing efficiency of the laminates after they were subjected to quasi-static impact. Specimens were tested in the undamaged, damaged and healed conditions using a commercial two-part epoxy healing agent (Cytec Cycom 823). Microscopic characterisation of the embedded HGF was also undertaken to characterise the effect on the host laminate fibre architecture.     

High-performance polymer coatings for carbon steel heat exchanger tubes in geothermal environments

The most critical issue in developing thermal conductive coatings for the interior surfaces of heat exchanger tubes made from mild carbon steel (MCS), which are used in geothermal power plants at temperatures ranging from 110° to 89°C, is the deposition of scales. These scales, induced by the brine, chemically adhere to the coating surfaces. One of the major factors governing the formation of a strong interfacial bond at interfaces between the coatings and scales was the brine-promoted hydrothermal oxidation of the coatings. In seeking coating unsusceptible to hydrothermal oxidation, two semi-crystalline thermoplastic polymers, polyphenylenesulfide (PPS) and polytetrafluoroethylene (PTFE)-blended PPS, were applied as interior surface coatings to the zinc phosphated MCS tubes. The PPS coating surfaces suffered some oxidation caused by their chemical affinity for FeCl₂ in geothermal brine. FeCl₂-promoted oxidation of PPS surfaces not only incorporated more oxygen into them, generating a sulfide sulfone sulfonic acid conformational transformation within the PPS, but also caused the disintegration of PPS, yielding fragmental polychloroaryl compound and ferrous sulfate (FeSO₄) derivatives. The FeSO₄ reaction product formed at the interfaces between the scale and PPS coating was soluble in water, so that the coatings could be easily removed by highly pressurized water. The oxidation of PPS was considerably inhibited by blending PTFE into it, forming coating surface unsusceptible to hydrothermal oxidation reactions with hot brine. The major reason for such inhibition of oxidation was the formation of a chemically inert PTFE layer segregated from the PPS layer at the outermost surface site of the coating. Hence, the scale easily flaked off from the PTFE-blended PPS coating surfaces. This characteristic of surface was similar to that of the stainless steel surfaces. Nevertheless, both PPS and PTFE-blended PPS coatings can be classified as scale-free coatings.